DNF metadata cache expiration and permission boundary on CentOS Stream

DNF metadata cache expiration on CentOS Stream is governed by the interaction between repo-provided expire and dnf.conf metadata_expire, with effective freshness taken as the minimum of the two values.

The cache is stored under /var/cache/dnf per repository and is root owned, creating a permission boundary where non-root users can query packages via dnf but cannot directly inspect or purge cache contents for troubleshooting.

With a rolling release model, long expire values can allow stale package lists to persist after upstream changes, and there is no documented hard maximum staleness cap independent of upstream metadata.

What configuration provides predictable freshness guarantees for CentOS Stream without relying solely on upstream expire? Should a hard maximum staleness cap be enforced by default? How should cache inspection be permitted within the existing permission boundary?